Developing apparatus

ABSTRACT

A photographic developing apparatus having a series of processing stations through which a tray carrying photographic slides is transported by a transfer mechanism. The transfer mechanism comprises at least one pair of crank arms which are rotatably mounted at one end thereof intermediate the processing stations, members journaled at the other ends of the arms for engaging the supporting rod of the tray, and a motor for rotating the crank arms through a complete revolution. A timer control device is provided for sequentially operating the transfer mechanism to thereby transport a tray from one processing station to another after a predetermined processing time has elapsed.

United States Patent Orr et al. 1 Feb. 15, 1972 [54] DEVELOPINGAPPARATUS 3,343,472 9/ 1967 Rosenberg ..95/94 [72] Inventors: Robert F.on, Livermore; Joseph H. 3,353,470 11/1967 Zane ..95/94 wyers Pl both ofcalm Primary ExaminerSamuel S. Matthews (73} Assignee: Fluoroware ofCalifornia, Inc. Assistant Examiner-Fred L, Braun 221 Filed: Mar. 18,1970 HPPe .[Zl] Appl. No.: 20,608 [57] ABSTRACT A photographicdeveloping apparatus having a series of [52] US. CL D, 1 18/423, 134/78,processing tations through which a [ray carrying photol34/142 graphicslides is transported by a transfer mechanism. The [5 Cl. ..G03dtransfer mechanism comprises at least one pair of crank arms [58] newSearch "95/89 39 94 R, 100; which are rotatably mounted at one endthereof intermediate 118/30, 423, 425; 134/7 142 the processingstations, members joumaled at the other ends of the arms for engagingthe supporting rod of the tray, and a [56] Reem C'ted motor for rotatingthe crank arms through a complete revolu- UNITED STATES PATENTS tion.timer control device is provided for sequentially operating the transfermechanism to thereby transport a tray 1,473 3/ 1 p 9! "95/39 from oneprocessing station to another after a predetermined 2, l processing timehas elapsed 902,861 11/1908 Danenhower... ....134/78 2,349,823 5/1944Howard ..95/89 10 Claims, 8 Drawing Figures l6 zzzzz-fifi. a4 o E-=5 :"Lx

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SHEET 1 BF 4 IN VENTOR$ MIMI/5V5 PMENYEIIFEB 151m '3; 641 gsos SHEET 2[IF 4 24 l Z6 Z4 I INVENTORS ROBERT F 02/? DEVELOPING APPARATUSBACKGROUND OF THE INVENTION In the electronic industry, photographicallyproduced masking slides are used in great numbers. These masks are usedin manufacturing microelectronic circuits such that each microelectroniccircuit produced consumes one slide in its production. This requiresprocessing of the slides in large numbers under conditions meeting therigid specifications imposed in this field. Processing of these slidesis complicated since, during the production run, slides of differentsizes or in different quantities or having different processingrequirements may be processed at the same time.

More particularly, we provide a developing apparatus for processingphotographic slides through a series of developing, fixing and rinsingbaths. The slides are supported in support means or trays each of suchsuspended from a carrier rod. The trays are serially transported fromone bath to the next in an individually timed sequence determinative ofthe duration of processing at each station.

The baths are equidistantly spaced along a processing line and thecarrier rods extend transversely of the line and beyond the margins ofthe baths with he individual rods supported in V-shaped sockets mediallyof the baths during the processing period.

A series of transfer mechanisms are positioned between adjacent bathsfor transporting each carrier tray and included slides between thebaths. Each transfer mechanism includes a pair of opposed cradlesjournaled at the distal ends of crank arms wherein orbiting of the crankarms will cause the cradles to intercept the ends of a carrier rod andtransport it from one set of V-shaped sockets to the next. The crankarms are carried on the ends of a shaft bridging the line intermediatethe bath stations. The shaft is rotated through one cycle of revolutionby an electric motor and control.

A sequence timer is actuated upon the arrival of a tray at a station andafter the proper processing duration starts the motor to initiate thetransfer cycle. A cam on each transfer shaft operates a switch tocontinue to supply power to the motor until the cradles are conveyedthrough a complete circuit.

The several processing baths are confined in tanks supported betweenlongitudinal frame members. Similarly, the V- shaped sockets aresupported on the longitudinal frame members outboard of the line oftanks. The transfer shafts are jour naled in bearings carried on theframe members at a position elevated from the sockets whereby, as thecradles orbit outboard of the sockets, the slide trays are elevated fromthe baths through a steep angle.

The framing of the station units is in modular form such that the linemay be made up ofa succession ofunits as determined by the numberofprocessing steps desired.

SUMMARY OF THE INVENTION It is a principal object of the presentinvention to provide a developing apparatus having a great degree offlexibility and which can process slides of different characteristics atthe same time. This is accomplished by providing the apparatus with aseries of processing baths and conveying the slides successively throughthe baths in individually timed sequences.

Another object is to provide such an apparatus which has a largethroughput of slides and which will accept mixed lots of individualtrays of slides and process them in a linear fashion through a series ofbaths and wherein the baths and their associated transfer mechanisms areintegral units with the duration of immersion in each bath beingindividually timed.

Still another object wherein each processing station is a whollycontained modular unit such that any number of stations may be linkedtogether to form an entire processing group.

A further object is to carry the slides in trays from one station to thenext on a transversely disposed carrier rod and to use the rod to alignthe trays in the baths and also initiate the timing cycle when the traysare lowered into the baths and wherein the carrier rod describes a pathof overlapping arcs between adjacent baths such that the trays enter andleave the baths at a steep angle.

Finally it is an object to provide such an apparatus along alongitudinally extending processing line wherein the baths and theirassociated controls are visually displayed to the operator in adjacentrelation and wherein the transfer mechanism is housed and substantiallyconcealed in shrouds to provide a safe environment for the operator.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred form of the invention isillustrated in the accompanying drawings forming a part of thisspecification, in which:

FIG. I is aperspective view of a developing apparatus constructed inaccordance with the present invention;

FIG. 2 is a fragmentary plan view of the apparatus shown in FIG. I withportions removed to view the underlying structure;

FIG. 3 is an.elevational section taken substantially along the plane ofline 33 in FIG. 2;

FIG. 4 is a fragmentary elevational section taken substantially alongthe plane of line 44 in FIG. 1;

FIG. 5 is an-exploded perspective view of the crank arm and cradlestructureof the transfer mechanism;

FIG. 6 is an elevational section of the cradle structure takensubstantially along the plane of line 6-6 in FIG. 5;

FIG. 7 is a cross-sectional view taken substantially along the plane ofline 7 7 in FIG. 1; and

FIG. 8 is a schematic and diagrammatic representation of the transfermechanism and associated control including the circuitry.

While only the preferred form of the invention is shown, it should beunderstood that various changes or modifications may be made within thescope of the claims attached hereto without departing from the spirit ofthe invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring particularly to FIGS.1, 2 and 3, the developing apparatus 11 is for processing photographicslides 12 and the like wherein the slides are carried in trays 13, eachbeing suspended from a carrier rod 14. The apparatus is in the form of aseries of processing stations 16 spaced along a processing line 17 andincludes holding sockets 18 positioned transversely of each station 16to support the carrier rod during processing of the slides at thatstation.

A series of transfer devices 19 are carried intermediate each stationfor transporting each carrier rod and its associated tray from onestation to the next in cradles 21 engageable with the ends of a carrierrod. The cradles 21 are journaled at the distal ends of crank arms 22and are spaced therealong to intercept a carrier rod on the sockets 18whereby orbiting of the crank arms 22 transports the carrier rod 14 andincluded tray 13 from one station to the nest independently of the othertransfer devices.

The several baths 23 each include the proper developing, fixing andrinsing agents or any other desirable processing agent. The baths arecarried in tanks 24 and are preferably constantly circulated through thetanks by way of suitable inlet and outlet openings 26. Furthermore, eachbath may be provided with suitable auxiliary devices 27 such as a pump28 and filter 29 for purifying or otherwise ensuring the properprocessing characteristics of the bath. These devices are convenientlyhoused in a bay 31 under the tanks 24 and are readily serviced throughsliding doors 32 in the cabinet 33. The tanks are of a size to acceptthe largest slide tray contemplated and still allow ready circulation ofthe liquid in the bath over the slides.

The baths are supported along the processing line l7 betweenlongitudinally extending frame members 34. Frame members 36 are spacedalong the line 17 transversely of members 34 for supporting the upperflanges 37 of the tanks. This supports the tanks at the proper spacingand elevation while allowing ready removal of any tank for replacementif necessary.

The slides 12 are carried through the baths in a vertical position intrays 13 of the type having an open grillwork for efficient liquidcirculation and draining. The trays 13 are suspended by invertedV-shaped hangers 38 from carrier rod 14. In operation, the rod iscarried transversely along the processing line of tanks and is of suchlength to extend from the hangers 38 equidistantly beyond the margins ofthe banks 24 and frame members 34. Each rod 14 is provided withshoulders 39 which center the hanger and suspended tray midway of itsends. Each rod also has equidistantly spaced relieved portions 41 whichrest in the holding sockets 18 when the tray is immersed in a bath. Thisensures that each tray of slides will be suspended in the properposition for processing in the bath and also for proper pickup by thetransfer mechanism.

As mentioned, integral transfer devices 19 are provided to transport theslides from one bath to the next. Each transfer device has a pair ofinterconnected cradles 21 which pick up the extreme ends of a carrierrod 14 and move it upwards and along a generally semicircular path fromone bath to the next succeeding bath. The cradles 21 have V-shapedrecesses 42 formed by converging faces 43a, 43b and 43c which provide alarge entrance area to facilitate picking up the rod ends and a smallerconfined area for precisely locating the rod ends for subsequentplacement in the next pair of holding sockets. Furthermore, the cradlesare journaled on crank arms 22 at a point above the recesses and abovethe center of gravity of the cradles. This again allows some tolerancein picking up the rod.

The journaling of the cradle on the crank arm is accomplished by alow-friction ball bearing 44. This hearing has an outer race 46, pressfit into a bore 47 in the crank arm, and an inner race 48 providing asleeve for capscrew 49. Screw 49 attaches the arm 22 to the cradle 21through a threaded hole 51 while a shoulder 52 on the sleeve providesproper spacing therebetween such that the cradle has ample freedom ofrotation about the arm. Correspondingly, the cradle is fashioned with alarge mass 53 to provide a desired low center of gravity to keep recess42 below the attachment point 51. This cooperation with the low-frictionbearing ensures that the V" of the recess is always pointed upward forproper pickup and also provides protection against tipping of a tray ofslides during transport.

The crank arms 22 are attached at their inner ends to a common driveshaft 61. This attachment is provided by keyways 56 and screws 57fitting complementary keys 58 and threaded bores 59 on either end of ashaft 61. Shaft 61 extends between the crank arms 22 across the line 17intermediate the baths and is journaled in bearing blocks 62 held toframe members 34 by screws 63. The axis of rotation of this shaft isslightly above the horizontal plane of the carrier rods when the carrierrods are resting on the holding sockets at the bath stations. Thisallows the path of rotation of the cradles to describe arcs whichoverlap the median plane of the adjacent baths such that the rod andincluded slide trays are picked up included lowered through a steepangle at each bath.

The drive shaft 61 if rotated through one revolution by an electricmotor 64 in response to the dictates of a control timer 66. The motor isof the gear type and drives pulley 67 through belt 68 and drive pulley69. A slip clutch may be interposed in this belt-pulley drive 71 toprevent breakage if any part of the transfer mechanism is jammed.

The holding sockets 18 are provided in proper position for pickup andrelease of a carrier rod by the transfer device. The sockets are madefrom angle stock and have a base 72 attached to frame members 34 byfasteners 73. The upstanding side 74 is cut into the appropriateV-shaped socket l8 and cooperates with relieved portion 41 of thecarrier rod to locate precisely each tray in a bath and the rod ends forsubsequent pickup.

As mentioned, the trays of slides are transferred along the line inresponse to a timer control 66 at each station. As is shown in FIG. 8,suitable electrical power is supplied through powerlines 76 and 77 to acontrol circuit 78. This circuit is repeated for each transfer mechanismand is determinative of the duration of processing at the anteriorstation adjacent that transfer mechanism. Each control circuit includesa feeler switch 79, responsive to the landings of a carrier rod at theanterior station, an electric timer 81 controlling switch 82, theelectric drive motor 64 and a cycle completion switch 83 responsive tothe rotary position of shaft 61 as indicated by cam 84.

Feeler switch 79 is carried on bracket 86 along frame member 34 underone of the holding sockets 18 and has an ac tuating rod 87 extendinginto the path of the carrier rod 14. Upon landing on the socket, thecarrier rod depresses the actuating rod 87 and causes the contacts ofswitch 79 to close. Power is then applied across line 88 and sequencetimer 8] starts its countdown. The timer 8] may be of any constructionwhich will provide a switching output after a specified time durationand is preferably readily adjustable over a time span greater than anyof the expected processing time periods.

After a specified processing time as measured by timer 8] has elapsed ata given tank, switch 82 is closed and power is fed along line 89 tomotor 64. Motor 64 will commence to rotate shaft 61 through belt andpulley drive 71 to orbit the crank arms toward the ends of carrier rod14 and lift the rod with cradles 21. The raising of the carrier rodreleases actuator rod 87 and allows spring 91 to open switch 79. Thisremoves power from line 88. Timer 81 will then open switch 82 andinternally reset for the next sequence. Prior to this, cam 84 on shaft61 is rotated onto a position to depress and close switch 83. Powercontinues to drive motor 64 through line 89 until the cradles have madeone complete orbit. As a carrier rod 14 is lowered onto the next orposterior station, a corresponding circuit is actuated to continue theprogression of slide trays along the processing line in the chosensequence.

In the preferred embodiment, the framing is modularized in units each ofwhich supports two tank stages on each frame unit. As mentioned,longitudinal frame members 34 provide the support for the tank carryingcross frame 36, the bearing 62 of shafts 61, the holding sockets 18 andthe brackets 86 of feeler switches 79. These frame members 34 areconveniently sectioned at points 92 (see FIG. 3) to form the necessarybreaks for the module units 93. These breaks are bridged by ties 94 toform the continuous line 17. Also, the ties 94 in turn provide theproper spacing for elevating the drive shaft bearings 62.

The sectioned longitudinal frame members 34 are supported in a boxlikesubframe 96 on columns 97. Subframes of neighboring modules are boltedtogether by bolts 98 to form a continuous ridged frame for theapparatus. As shown in FIG. 7, the subframe 96, in cross section,includes a base 99 and upstanding columns 101. The columns 101 supportthe cabinet 33. Also the frame members 34 are spaced so the crank armsof the transfer mechanism can orbit. Cross-bracing 102 and 103 is alsoprovided while the motor 64 is conveniently mounted on one of the braces103 by fasteners 104. A platform 106 is also provided to support aplumbing device 27 such as a pump 28 and a filter 29.

The cabinet 33 includes a canted surface 107 forming a control panel forpositioning the timer 66 and temperature and flow controls adjacenttheir designated baths. The cabinet also forms shrouds along the sidesof the line, behind which the transfer mechanism is housed andsubstantially hidden from view. Similarly the drive shaft 61 andbearings 62 of the transfer mechanism are housed under shrouds 108 toprotect them from any dripping bath fluid. The cabinet shroud hasscalloped shaped cutouts 109 along its depending side. Shrouds 108 haveupstanding semicircular shaped sides 111 which are complementary to andfit within cutouts 109. In this way only an area as defined by the pathsof the carrier rods need be open and exposed to the inner workings ofthe rest of the mechanisms. An outer cabinet defined by dotted lines 112may correspondingly be constructed around any number of modules.

The apparatus also includes loading stage 113 and unloading stage 114 atthe respective ends of the processing line 17. This permits automatichandling of the slides without the constant supervision of an attendant.Each of these stages consists of spaced chain conveyors 116 and 117 onwhich the carrier rods are held prior to and after processing. Theloading conveyor 116 advances the carrier rods to a holding station 118,initial to the processing cycle. The unloading conveyor 117 accepts thecarrier rods of the processed slides and is incrementally advanced tospace them along its length.

In operation, and prior to running of the slides, each tank is filledwith an appropriate processing fluid and its temperature and flowmonitored at each station on the control panel. Similarly, the desiredduration of processing at each station is selected on the associatedtimer control 66.

Next the transparent hood of the loading stage is raised and the traysare placed therein with he carrier rods 14 resting on chain conveyor116. The conveyor chains are driven toward the baths by an appropriatemotor (not shown) until a rod reaches the holding station 118 of thefirst transfer mechanism. At this station a switch is engaged to stopthe conveyor and actuate the first sequence timer. This timer is set fora longer period than any of the processing timers to ensure that thetrays will not bunch up at some station along the line.

After the first sequence timer 66:! has operated for the selectedperiod, the first transfer device 19 picks up the ends of the carrierrod 14 and transports the tray to the first processing station. Thisstation is usually a prerinse or cleaning bath. As the tray of slidesenters this bath, a second timer 66b designated for this bath isactuated through a feeler switch 79 in response to the lowering of rod14. After the appropriate period in the bath, timer 66b energizes aninternal relay coil and closes switch 82. A second transfer mechanism19, driven by a motor 64 in response to the closing of switch 82, thenlifts the rod and included tray out of the first bath. As the rod islifted, switch 82 opens and allows the timer to reset. At this time, cam84 on shaft 61 has closed switch 83 to continue to supply power to motor64. When the transfer mechanism reaches the next bath, the rod ends willcontact the holding socket l8 and actuating rod 87 of switch 79 to startthe third timer. The transfer mechanism continues to rotate afterdepositing the carrier rod on the holding sockets to some resting placethereunder. This resting place is, of course, out of the paths of itsneighboring transfer mechanisms. At this point, the cam 84 on shaft 61will allow switch 83 to open under pressure from spring 1 19.

This procedure is repeated at each station through the entire line ofbaths with the duration in each bath varying by the time selected on therespective timer controls. If desired, the developing bath may beprovided by two tanks to provide the longer period needed for the bathwithout unduly slowing down the total processing time of the other slidetrays.

The duration and other parameters of the processing may be monitoredfrom the designated control devices placed opposite each station on thecontrol panel. Similarly, a tray of slides may be followed visuallyalong the processing line and appropriate changes made for it at eachstation.

Any combination of tray and slide sizes that are within the range of theapparatus may be mixed in the same run since the control is responsiveto and determinative only of the position of the carrier rod.

At the end of the line each carrier rod and included slide tray isdeposited at an unloading stage 114. This stage has a pair of conveyorchains 117 similar to those of the loading stage for holding a quantityof trays of slides. Upon arriving at this stage, a switch is actuated toadvance the conveyor a specified increment in any well-known manner tospace the slide trays along the conveyor chains. This stage may alsoinclude a dryer if desired.

From the foregoing, it will be seen that the developing apparatus of thepresent invention provides for processing photographic slides in anefficient manner by transporting them along a processing lineindependently of other slides being processed.

We claim:

1. A developing apparatus for processing photographic slides and thelike, comprising a series of processing stations spaced along aprocessing line, a carrier rod having means thereon for supporting saidphotographic slides therefrom, holding sockets at opposite sides of eachstation to support the carrier rod and slides during processing of theslides at the station, a series of transfer devices each positionedintermediate adjacent stations for transporting the carrier rod andslides from one station to the next station, each said transfer devicecomprising a pair of crank arm means rotatably mounted at one endthereof at opposite sides of the stations, means journaled at the otherend of said crank arm means for supporting engagement with said carrierrod and spaced to intercept the carrier rod held on the sockets uponrotation of the crank arm means, and means connected with the crank armmeans to rotate them through a complete revolution so that the journaledmeans on said crank arm means engage a carrier rod and transport thecarrier rod from one station to an adjacent station, where a successivecrank arm means engages and transports the carrier rod to a furtherstation upon rotation of said successive crank arm means.

2. The apparatus as defined in claim 1 wherein said journaled meanscomprises a cradle, the axis of revolution of said crank arms being in aplane elevated above a carrier rod when supported on the holding socketssuch that the rod is intercepted by the cradles to raise the traysthrough an arc of approximately l and from one station to the next.

3. The apparatus as defined in claim 1 wherein the crank arm means arerotatably mounted outboard of said holding sockets such that thejournaled means intercept the ends of a carrier rod and wherein thecrank arm means are interconnected by a shaft bridging the processingline intermediate the stations.

4. The apparatus as defined in claim 1 wherein rotation of said crankarm means is responsive to a timer control at each station.

5. The apparatus as defined in claim 1 wherein the holding sockets haveconverging supporting surfaces to center the rods medially of the baths.

6. The apparatus of claim 1 wherein the journaled means comprise cradleshaving converging surfaces to center the carrier rod thereon andprecisely position the rod for proper placement at the next station.

7. The apparatus as defined in claim 1 wherein said plurality of tanksare arranged in a line and spaced apart a like distance in such line,said means for supporting the slides from each rod comprising a trayfitting in the tanks, said transfer means picking up a tray in one tankand moving the tray to the next tank for immersion in the liquid in thattank.

8. Apparatus as in claim 7 wherein timing means are provided for timingthe period of tray immersion in a tank.

9. A developing apparatus for processing photographic slides and thelike wherein the slides are carried in trays suspended from a carrierrod comprising spaced frame members extending longitudinally along aprocessing line, a series of bath stations disposed equidistantly alongsaid line with the baths confined in tanks supported between thelongitudinal frame members, holding sockets positioned on the said framemembers medially of each bath station for supporting a carrier rodduring the processing of the slides at that station, and transferdevices for transporting the carrier rods and included trays betweenadjacent baths and having a shaft journaled in bearings supported by theframe members intermediate the holding sockets, crank arms carried bythe shaft outboard of the said frame members, cradles journaled inlow-friction bearings at the distal ends of the crank arms andpositioned to inscribe a path intercepting the ends of a carrier rodheld at an adjacent holding socket, said cradles having a carryingrecess defined by three converging faces which act to center and alignsaid carrier rod during transport and wherein said recess is spacedbelow the point of attachment of the low-friction bearing.

10. A developing apparatus for processing photographic slides and thelike wherein the slides are carried in trays suspended from a carrierrod and comprising a series of processing stations spaced along aprocessing line, holding sockets positioned transversely of each stationto support the carrier rod during processing of the slides at thestation, a series of transfer devices each positioned intermediateadjacent stations for transporting the carrier rod from one station tothe next including cradles engageable with the ends of said carrier rod,a pair of crank arms, said cradles being journaled at the distal ends ofthe crank arms and spaced to intercept the carrier rod held on thesockets, means for oscillating the crank arms to transport the carrierrod and included tray from one station to the next station, and anelectric motor coupled to said transfer mechanism to orbit said crankarms, said motor being responsive to a timer control at the precedingstation, the timer control is actuated upon the carrier rod arriving atthe preceding station and is determinative of the duration of processingat said last-mentioned station.

1. A developing apparatus for processing photographic slides and thelike, comprising a series of processing stations spaced along aprocessing line, a carrier rod having means thereon for supporting saidphotographic slides therefrom, holding sockets at opposite sides of eachstation to support the carrier rod and slides during processing of theslides at the station, a series of transfer devices each positionedintermediate adjacent stations for transporting the carrier rod andslides from one station to the next station, each said transfer devicecomprising a pair of crank arm means rotatably mounted at one endthereof at opposite sides of the stations, means journaled at the otherend of said crank arm means for supporting engagement with said carrierrod and spaced to intercept the carrier rod held on the sockets uponrotation of the crank arm means, and means connected with the crank armmeans to rotate them through a complete revolution so that the journaledmeans on said crank arm means engage a carrier rod and transport thecarrier rod from one station to an adjacent station, where a successivecrank arm means engages and transports the carrier rod to a furtherstation upon rotation of said successive crank arm means.
 2. Theapparatus as defined in claim 1 wherein said journaled means comprises acradle, the axis of revolution of said crank arms being in a planeelevated above a carrier rod when supported on the holding sockets suchthat the rod is intercepted by the cradles to raise the trays through anarc of approximately 180* and from one station to the next.
 3. Theapparatus as defined in claim 1 wherein the crank arm means arerotatably mounted outboard of said holding sockets such that thejournaled means intercept the ends of a carrier rod and wherein thecrank arm meAns are interconnected by a shaft bridging the processingline intermediate the stations.
 4. The apparatus as defined in claim 1wherein rotation of said crank arm means is responsive to a timercontrol at each station.
 5. The apparatus as defined in claim 1 whereinthe holding sockets have converging supporting surfaces to center therods medially of the baths.
 6. The apparatus of claim 1 wherein thejournaled means comprise cradles having converging surfaces to centerthe carrier rod thereon and precisely position the rod for properplacement at the next station.
 7. The apparatus as defined in claim 1wherein said plurality of tanks are arranged in a line and spaced aparta like distance in such line, said means for supporting the slides fromeach rod comprising a tray fitting in the tanks, said transfer meanspicking up a tray in one tank and moving the tray to the next tank forimmersion in the liquid in that tank.
 8. Apparatus as in claim 7 whereintiming means are provided for timing the period of tray immersion in atank.
 9. A developing apparatus for processing photographic slides andthe like wherein the slides are carried in trays suspended from acarrier rod comprising spaced frame members extending longitudinallyalong a processing line, a series of bath stations disposedequidistantly along said line with the baths confined in tanks supportedbetween the longitudinal frame members, holding sockets positioned onthe said frame members medially of each bath station for supporting acarrier rod during the processing of the slides at that station, andtransfer devices for transporting the carrier rods and included traysbetween adjacent baths and having a shaft journaled in bearingssupported by the frame members intermediate the holding sockets, crankarms carried by the shaft outboard of the said frame members, cradlesjournaled in low-friction bearings at the distal ends of the crank armsand positioned to inscribe a path intercepting the ends of a carrier rodheld at an adjacent holding socket, said cradles having a carryingrecess defined by three converging faces which act to center and alignsaid carrier rod during transport and wherein said recess is spacedbelow the point of attachment of the low-friction bearing.
 10. Adeveloping apparatus for processing photographic slides and the likewherein the slides are carried in trays suspended from a carrier rod andcomprising a series of processing stations spaced along a processingline, holding sockets positioned transversely of each station to supportthe carrier rod during processing of the slides at the station, a seriesof transfer devices each positioned intermediate adjacent stations fortransporting the carrier rod from one station to the next includingcradles engageable with the ends of said carrier rod, a pair of crankarms, said cradles being journaled at the distal ends of the crank armsand spaced to intercept the carrier rod held on the sockets, means foroscillating the crank arms to transport the carrier rod and includedtray from one station to the next station, and an electric motor coupledto said transfer mechanism to orbit said crank arms, said motor beingresponsive to a timer control at the preceding station, the timercontrol is actuated upon the carrier rod arriving at the precedingstation and is determinative of the duration of processing at saidlast-mentioned station.